For a number of products it has become increasingly important to be able to package them in so-called tamperproof containers, i.e. containers which can be delivered to the purchaser or the consumer in a form providing security to the user against prior opening of the container or a tell-tale signal of such unauthorized access to the contents. Closures for screw-type containers for this purpose generally comprise a ring, which can be termed a security ring, whose separation from the closure bears witness to the fact that the container has been opened.
Tamperproof containers providing such security can be in the form of cans, bottles or flasks, and the tamperproof closure may be provided for safety or health reasons, or simply to assure the consumer that there has been no adulteration or substitution of the contents.
Tamperproof containers may be used for combustibles, for pharmaceuticals, for cosmetics, for alcoholic beverages and even for a variety of industrial liquids for safety purposes. In addition, such closures serve as guarantees of the quantity and quality of the contents.
It is known, as noted, to provide a screw-type closure with a safety ring connected to the body of the closure by a readily rupturable web or by other ligatures so that, when the closure is unscrewed for the first time, this ring engages a shoulder on the neck of the container and is held back as the remainder of the closure is withdrawn, thereby rupturing the web and separating the ring from the body of the closure.
The first opening of the container thus results in such separation and the separation of the ring can be immediately noted by any subsequent user or by the consumer and will be associated with some type of tampering with the closure. When the closure is formed from a synthetic resin material, it is difficult to provide it in one piece with the ring and at the same time ensure perfect sealing of the container mouth. The problems involved include sealing, tight fitting of the closure and engagement of the ring over the collar, conditions which may not be mutually compatible in earlier devices, especially where perfect sealing is required in the pharmaceutical industry.
It is not uncommon, therefore, to make a closure for such purposes from three pieces, namely, one piece which has as its primary function the formation of a seal, another piece whose primary function is that of a holder for the seal, and a third piece which cooperates with the holder and whose primary function is that of a carrier of the ring. In general, therefore, prior-art tamperproof closures especially for systems in which a high degree of sealing is mandatory, have been complex, difficult to use, and expensive to manufacture and mount upon the container.